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Many endurance athletes perform specific blocks of training in hot environments in "heat stress training camps." It is not known if physiological threshold heart rates measured in temperate conditions are reflective of those under moderate environmental heat stress. A total of 16 endurance-trained cyclists and triathletes performed incremental exercise assessments in 18°C and 35°C (both 60% relative humidity) to determine heart rates at absolute blood lactate and ventilatory thresholds. Heart rate at fixed blood lactate concentrations of 2, 3, and 4 mmol·L−1 and ventilatory thresholds were not significantly different between environments (P >.05), despite significant heat stress-induced reductions in power output of approximately 10% to 17% (P <.05, effect size = 0.65–1.15). The coefficient of variation for heart rate at these blood lactate concentrations (1.4%−2.9%) and ventilatory thresholds (2.3%−2.7%) between conditions was low, with significant strong positive correlations between measurements in the 2 environments (r =.92–.95, P <.05). These data indicate heart rates measured at physiological thresholds in temperate environments are reflective of measurements taken under moderate environmental heat stress. Therefore, endurance athletes embarking on heat stress training camps can use heart rate–based thresholds ascertained in temperate environments to prescribe training under moderate environmental heat stress. [ABSTRACT FROM AUTHOR]

Objective: To measure symptoms of anxiety, depression and hopelessness in a sample of young Pacific adults living in Auckland, New Zealand during the 2020/2021 COVID-19 pandemic and identify protective factors. Methods: Participants were 267 Pacific adults (58% female) who completed a survey online. Analyses included descriptive statistics, correlations, linear regression and symptom network analysis. Results: Around 25% of the sample scored in the range for moderate to severe anxiety and 10% for moderate to severe depression on standard measures. Almost 40% indicated that they found the first lockdown very stressful and 55% noted that some members of their family found it stressful. Only 16% worried about COVID-19 and their future quite a bit or constantly, while another 25% worried sometimes. Self-compassion and Pacific Identity had moderate, negative correlations, and Worry about COVID-19 had weak positive correlations, with anxiety, depression, hopelessness and perceived stress. Conclusion: These results suggest that, while the prevalence of depression and anxiety are quite high among this population, fostering ethnic identity and self-compassion in Pacific children and adolescents might protect against developing depression and anxiety. [ABSTRACT FROM AUTHOR]

This study investigated the effect of the racemic β-hydroxybutyrate (βHB) precursor, R,S-1,3-butanediol (BD), on time-trial (TT) performance and tolerability. A repeated-measures, randomized, crossover study was conducted in nine trained male cyclists (age, 26.7 ± 5.2 years; body mass, 69.6 ± 8.4 kg; height, 1.82 ± 0.09 m; body mass index, 21.2 ± 1.5 kg/m²; ...O2peak,63.9 ± 2.5 ml⋅kg-1⋅min-1; Wmax, 389.3 ± 50.4 W). Participants ingested 0.35 g/kg of BD or placebo 30 min before and 60 min during 85 min of steady-state exercise, which preceded a ~25- to 35-min TT (i.e., 7 kJ/kg). The ingestion of BD increased blood D-βHB concentration throughout exercise (0.44-0.79 mmol/L) compared with placebo (0.11-0.16 mmol/L; all p < .001), which peaked 1 hr following the TT (1.38 ± 0.35 vs. 0.34 ± 0.24 mmol/L; p < .001). Serum glucose and blood lactate concentrations were not different between trials (all p > .05). BD ingestion increased oxygen consumption and carbon dioxide production after 20 min of steady-state exercise (p = .002 and p = .032, respectively); however, no further effects on cardiorespiratory parameters were observed. Within the BD trial, moderate to severe gastrointestinal symptoms were reported in five participants, and low levels of dizziness, nausea, and euphoria were reported in two participants. However, this had no effect on TT duration (placebo, 28.5 ± 3.6 min; BD, 28.7 ± 3.2 min; p = .62) and average power output (placebo, 290.1 ± 53.7 W; BD, 286.4 ± 45.9 W; p = .50). These results suggest that BD has no benefit for endurance performance. [ABSTRACT FROM AUTHOR]

Purpose: To determine the effect of different high-intensity interval-training (IT) sessions on the postexercise recovery response and time course across varying recovery measures. Methods: A total of 13 highly trained rowers (10 male and 3 female, peak oxygen uptake during a 6-min maximal test 4.9 [0.7] L·min−1) completed 3 IT sessions on a rowing ergometer separated by 7 d. Sessions consisted of 5 × 3.5 min, 4-min rest periods (maximal oxygen uptake [VO2max]); 10 × 30 s, 5-min rest periods (glycolytic); and 5 × 10 min, 4-min rest periods (threshold). Participants were instructed to perform intervals at the highest maintainable pace. Blood lactate and salivary cortisol were measured preexercise and postexercise. Resting heart-rate (HR) variability, post-submaximal-exercise HR variability, submaximal-exercise HR, HR recovery, and modified Wingate peak and mean power were measured preexercise and 1, 10, 24, 34, 48, 58, and 72 h postexercise. Participants resumed training throughout the measurement period. Results: Between-groups short-term response differences (1 h post-IT) across IT sessions were trivial or unclear for all recovery variables. However, post-submaximal-exercise HR variability demonstrated the longest recovery time course (threshold = 37.8 [14.2], glycolytic = 20.2 [11.0], and VO2max = 20.6 [15.2]; mean [h] ± confidence limits). Conclusion: Short-term responses to threshold, glycolytic, and VO2max IT in highly trained male and female rowers were similar. Recovery time course was greatest following threshold compared with glycolytic and VO2max-focused training, suggesting a durational influence on recovery time course at HR intensities ≥80% HRmax. As such, this provides valuable information around the programming and sequencing of high-intensity IT for endurance athletes. [ABSTRACT FROM AUTHOR]

The primary aim of this study was to examine if biomarker and/or self-reported data could predict upper respiratory tract symptom (URTS) risk in elite field hockey players. The secondary aim was to investigate the effect of the additional stressor 'repeated heat exposure' on measures of thermoregulation and immunity. A prospective cohort repeated measures study design was used to collect URTS, household illness, self-reported wellness, biomarker and thermoregulatory data from elite male field hockey players (n = 19), during an 8-week training and competition period that simulated the preparatory and competition phases of the 2020 Tokyo Olympics. Heat response testing (HRT) was performed at the beginning of the study period, following heat acclimation (HA) and following an intensified competition period (ICP) played in hot and humid conditions (27–37°C and 53–80% relative humidity). Univariate frailty analysis demonstrated that illness in players' households (Hazard ratio (HR: 4.90; p < 0.001)) and self-reported stress (HR: 0.63; p = 0.043) predicted players' risk for URTS. Additionally, low baseline resting salivary secretory immunoglobulin A (SIgA) concentration predicted players' "potential" URTS risk (p = 0.021). The additional stressor "repeated heat exposure" was found to facilitate partial thermoregulatory adaptation without attenuating resting immune functions. In conclusion, lifestyle and behavioural factors (i.e. household illness and stress) influenced players risk for URTS more so than sport-related stressors. Furthermore, repeated heat exposure did not appear to compromise players resting immunity. To assess athletes' risk for URTS, baseline screening of SIgA concentration and regular monitoring of self-reported lifestyle and behavioural data are recommended. Highlights Self-reported illness in players' households and higher self-reported stress significantly predicted increased upper respiratory tract symptom risk. Low baseline salivary secretory immunoglobulin A concentration predicted players "potential" URTS risk. Repeated heat exposures facilitated partial thermoregulatory adaptation without altering resting immunity. [ABSTRACT FROM AUTHOR]

This study assessed the selected peripheral blood haematological parameters and metabolite profiles linked to liver, serum and muscle samples in 3‐year‐old male (weight = 131.19 ± 29.24 g; total length = 21.33 ± 1.20 cm; n = 5) and female (122.96 ± 27.04 g; total length = 21.09 ± 1.09 cm; n = 5) giant kokopu (Galaxias argenteus) broodstock cultured at 12°C and 16°C. Temperature and sex did not influence haematocrit values or counts of total blood cells, erythrocytes and leucocytes. However, fish reared at 16°C had higher thrombocyte counts, whereas those kept at 12°C exhibited the highest proportion of lymphocytes. At the metabolic level, sex was the main factor that influenced metabolite levels across tissues, with particularly higher amino acid metabolites in liver of females. Changes linked to the interaction between temperature and sex showed significant differences in fatty acid profiles of liver, and in amino acids in muscle and serum samples. Males kept at 16°C exhibited decreased levels of myristic acid and nonadecanoic acid linked to homeoviscous adaptation. In females, levels for energy metabolites including tyrosine and aspartic acid (in muscle), and alanine (in serum) were disturbed at 16°C. The study provides insights into preliminary haematological and metabolic effects associated with sex and temperature in galaxiids. [ABSTRACT FROM AUTHOR]

Arbitrarily primed polymerase chain reaction (AP-PCR) are used in analyzing DNA fingerprints of Vibrio isolates involved in syndrome 93. The latter is a shrimp disease causing mass mortality and significant decrease in yields and survival rates. The Vibrio strains have been linked with shrimp disease outbreaks in Japan and New Caledonia. The use of AP-PCr allows clusters identified within the species of Vibrio penaeicida to be related to their area of origin as well as discriminating between Japanese and New Caledonian isolates.